Electrical distribution box placed on elevator shaft wall

Electrical distribution or control boxes can be installed on elevator shaft walls if proper conduit, fire protection, and code compliance measures are followed.

Code and Safety Requirements

Electrical wiring in elevator shafts or hoistways must comply with the National Electrical Code (NEC). Conductors and cables, except for traveling cables, must be installed in rigid metal conduit (RMC), intermediate metal conduit (IMC), electrical metallic tubing (EMT), rigid nonmetallic conduit (RNC), or wireways, or use Type MC, MI, or AC cable . A 2014 NEC exception allows listed cord- and plug-connected equipment to be installed without a raceway, but this is limited to specific devices like monitors or displays .

Conduit and Mounting Considerations

Both rigid and flexible conduits can be mounted on elevator shaft walls, including exterior walls, provided they are properly supported with hangers or connectors . PVC conduits are often preferred for above-ground installations due to corrosion resistance, while metal conduits provide additional mechanical protection . When using an existing electrical box, a box extension may be required to accommodate conduit entry .

Fire-Rated Shaft Wall Systems

Elevator shafts are typically constructed with fire-rated shaft walls, often using gypsum panels and metal studs, to protect occupants and maintain egress routes . Fire-rated shaft walls allow for wall penetrations for conduits and control boxes if the penetrations are properly sealed and the assembly maintains its fire rating . Control boxes installed in shaft walls should include fireproof elements around cable openings to prevent fire propagation into the shaft .

Control Box Design

Elevator control boxes can be mounted on the shaft wall at floor level and may include a fireproof door for protection of electrical subassemblies . Cables entering the box should be clamped and surrounded by fireproof elements to maintain safety. Some designs allow the box to stand on the floor in a recess, providing stability and access for maintenance .

Practical Recommendations

• Ensure all wiring and conduits comply with NEC 620.21 and related sections .
• Use fire-rated shaft wall assemblies and seal all penetrations to maintain fire protection .
• Provide proper access to the control box for maintenance and inspection.
• Support conduits with hangers and use appropriate connectors or box extensions .
• Consider NEMA-rated enclosures if the box is near the pit floor or exposed to potential moisture . By following these guidelines, an electrical distribution or control box can be safely and code-compliantly installed on an elevator shaft wall.